JP5457803B2 - Hot water storage hot water supply system - Google Patents

Description

  The present invention relates to a hot water storage type hot water supply system that performs instant hot water.

  Conventionally, there is a hot water storage type hot water supply system in which water is boiled by a heat pump and hot water stored in a hot water storage tank is supplied to a hot water use terminal such as a currant or a dishwasher. Hot water storage tanks are often installed outdoors together with a heat pump, and the piping distance from the tank to the terminal where hot water is used is long, so if the time when hot water is not used increases, the temperature of the hot water in the piping decreases and the use of hot water begins. Sometimes it is necessary to wait until the hot water remaining in the pipe is replaced with the hot water sent from the hot water storage tank. Therefore, when the hot water temperature in the pipe drops, the hot water pump returns the hot water in the pipe to the hot water storage tank, and the hot water in the hot water storage tank is sent to the pipe and circulated to prevent the hot water temperature in the pipe from dropping. Therefore, there is known a hot water storage type hot water supply system that performs hot water that allows hot water to be discharged immediately at the start of hot water use (see, for example, Patent Document 1).

  An example of such a hot water storage type hot water supply system will be described with reference to FIG. The hot water storage hot water supply system 101 includes a hot water storage tank 102 for storing hot water and heated water, a heat pump 103 for heating water in the hot water storage tank 102, a control unit 104 for controlling the operation of the heat pump 103, and the hot water storage tank 102. A high-temperature hot water supply pipe 105 for supplying high-temperature hot water and a mixed hot-water supply pipe 106 for supplying medium-temperature mixed hot water are provided.

  The lower layer of the hot water storage tank 102 is connected to a water supply pipe 171 that supplies water. Further, the lower layer portion of the hot water storage tank 102 is connected to the heat pump 103 via the pipe 172, and the water in the lower layer portion of the hot water storage tank 102 is heated by the heat pump 103. The heat pump 103 has a pump 131 that sends heated hot water to the hot water storage tank 102. The heat pump 103 is connected to the upper layer portion of the hot water storage tank 102 via a pipe 173 and supplies heated hot water to the upper layer portion of the hot water storage tank 102.

  The upper layer portion of the hot water storage tank 102 is connected to a high temperature hot water supply port 151 via a high temperature hot water supply pipe 105, and the high temperature hot water supply pipe 105 is provided with a temperature sensor 152 for detecting the temperature of the hot water in the pipe. A high temperature hot water return pipe 153 for returning hot water in the high temperature hot water supply pipe 105 to the hot water storage tank 102 is branched from the vicinity of the high temperature hot water supply opening 151 of the high temperature hot water supply pipe 105. 154 is provided.

  The mixed hot water pipe 106 is a three-way valve that connects a high temperature hot water pipe 161 branched from the high temperature hot water pipe 105, an intermediate temperature hot water pipe 162 that takes out hot water in the middle layer of the hot water storage tank 102, and a high temperature hot water pipe 161 and an intermediate temperature hot water pipe 162. 163, a mixing valve inlet pipe 164 connected to the three-way valve 163, a mixing valve inlet pipe 165 branched from the water supply pipe 171, a mixed hot water from the mixing valve inlet pipe 164, and a water supply from the mixing valve inlet pipe 165 And a mixing hot water pipe 168 that connects the mixing valve 166 and the mixing hot water supply port 167. The mixed hot water pipe 168 is provided with a temperature sensor 169 for detecting the hot water temperature in the pipe.

  Next, the operation of the hot water storage type hot water supply system 101 will be described. When the high temperature hot water supply port 151 is opened, the water supplied from the water supply pipe 171 enters the lower layer of the hot water storage tank 102 by the supply water pressure, the high temperature hot water in the upper layer of the hot water storage tank 102 is pushed up, and passes through the high temperature hot water supply pipe 105. Hot water is supplied from 151. When the mixed hot water supply pipe 167 is opened, the control unit 104 switches either the high temperature hot water from the high temperature hot water discharge pipe 161 or the intermediate temperature hot water from the medium temperature hot water supply pipe 162 according to the set temperature of the mixed hot water to be discharged. The hot water thus switched and the water supplied from the mixing valve inlet pipe 165 are sent to the mixing valve 166 by the feed water pressure, and mixed hot water is supplied from the mixed hot water pipe 167 through the mixed hot water pipe 168.

  The controller 104 drives the hot water supply pump 154 when the hot water temperature in the high temperature hot water supply pipe 105 detected by the temperature sensor 152 becomes lower than a predetermined temperature. Hot water in the high temperature hot water supply pipe 105 is returned to the middle layer of the hot water storage tank 102 via the high temperature hot water return pipe 153, and high temperature hot water in the upper layer of the hot water storage tank 102 is sent to the high temperature hot water supply pipe 105. Hot water in the return pipe 153 circulates. When the hot water temperature detected by the temperature sensor 152 becomes higher than a predetermined temperature, the hot water supply pump 154 is stopped. In this way, the hot water temperature in the high temperature hot water supply pipe 105 is always equal to or higher than the predetermined temperature, so that the high temperature hot water is discharged immediately when the high temperature hot water supply port 151 is opened.

  However, in such a hot water storage hot water supply system 101, the hot water in the mixed hot water pipe 168 is not returned to the hot water storage tank 102, so that the hot water in the mixed hot water pipe 168 is newly added even if the mixed hot water supply port 167 is opened. It is necessary to wait until the mixed hot water is replaced, which is inconvenient. Moreover, since the hot water in the mixed hot water pipe 168 must be thrown away until it is replaced, the hot water is wasted.

JP 2008-157551 A

  An object of the present invention is to solve the above-described problem, and to provide a hot water storage type hot water supply system that can immediately discharge hot water of medium temperature without wasting hot water.

In order to achieve the above object, the invention of claim 1 includes a hot water storage tank that is connected to a water supply pipe and stores hot water heated by water supply, a heating source that heats the water in the hot water storage tank, and an operation of the heating source. A control unit for controlling, a high temperature hot water supply pipe for supplying hot water in the hot water storage tank, a mixed hot water supply pipe for supplying hot water mixed with high temperature hot water or medium hot water in the hot water storage tank, and water supplied from the water supply pipe, A hot water storage system comprising a mixed hot water supply system for returning hot water in the mixed hot water pipe to the hot water storage tank for immediate hot water, wherein the mixed hot water pipe is an upper layer part of the hot water storage tank or the high temperature hot water pipe. A high temperature hot water pipe connected to the hot water storage tank, a medium temperature hot water pipe connected to the middle layer of the hot water storage tank, a three-way valve connecting the high temperature hot water pipe and the intermediate temperature hot water pipe, and a mixture for supplying hot water connected to the three-way valve Branch from the valve hot water pipe and the water supply pipe A mixing valve inlet pipe, a mixing valve for mixing hot water from the mixing valve inlet pipe and feed water from the mixing valve inlet pipe, and a mixing hot pipe for discharging hot water mixed by the mixing valve; The return hot water pipe is branched from the mixed hot water pipe and connected to a middle layer portion that is a middle temperature portion of the hot water storage tank, and has a hot water supply pump that supplies hot water in the mixed hot water pipe to the hot water storage tank. It is what.

The invention of claim 2 is a hot water storage tank that is connected to a water supply pipe and stores hot water heated by the water supply, a heating source that heats water in the hot water storage tank, a control unit that controls the operation of the heating source, A hot water supply pipe for supplying hot water in the hot water storage tank, a mixed hot water pipe for supplying hot water mixed with hot water or medium hot water in the hot water storage tank, and water supplied from the water supply pipe, and the mixing for instant hot water A hot water storage hot water system comprising a mixed return hot water pipe for returning hot water in a hot water pipe to the hot water storage tank, wherein the mixed hot water pipe is a high temperature hot water pipe connected to an upper layer portion of the hot water storage tank or the high temperature hot water pipe. A medium temperature hot water pipe connected to the middle layer of the hot water storage tank, a three-way valve connecting the high temperature hot water pipe and an intermediate temperature hot water pipe, a mixed valve hot water pipe connected to the three-way valve and feeding hot water, and the water supply A mixing valve inlet pipe branched from the pipe; A mixing valve for mixing hot water from the valve inlet hot water pipe and feed water from the mixing valve inlet water pipe, and a mixed hot water pipe for discharging the hot water mixed by the mixing valve; A hot water supply pump that branches from the pipe and is connected to the mixing valve inlet pipe without being connected to the hot water storage tank, and feeds hot water in the mixed hot water pipe to the mixing valve inlet pipe .

  The invention of claim 3 is a hot water storage tank that is connected to a water supply pipe and stores hot water heated with water supply, a heating source that heats water in the hot water storage tank, a control unit that controls the operation of the heating source, A hot water supply pipe for supplying hot water in the hot water storage tank, a mixed hot water pipe for supplying hot water mixed with hot water or medium hot water in the hot water storage tank, and water supplied from the water supply pipe, and the mixing for instant hot water A hot water storage hot water system comprising a mixed return hot water pipe for returning hot water in a hot water pipe to the hot water storage tank, wherein the mixed hot water pipe is a high temperature hot water pipe connected to an upper layer portion of the hot water storage tank or the high temperature hot water pipe. A medium temperature hot water pipe connected to the middle layer of the hot water storage tank, a three-way valve connecting the high temperature hot water pipe and an intermediate temperature hot water pipe, a mixed valve hot water pipe connected to the three-way valve and feeding hot water, and the water supply A mixing valve inlet pipe branched from the pipe; A mixing valve for mixing hot water from the valve inlet hot water pipe and feed water from the mixing valve inlet water pipe, and a mixed hot water pipe for discharging the hot water mixed by the mixing valve; Branch from the pipe, branch to a hot water intermediate temperature pipe connected to the hot water storage tank and a hot water cold pipe connected to the water supply pipe via a second three-way valve for switching the hot water return destination of the mixed hot water, A hot water supply pump for supplying hot water to the return hot water intermediate temperature pipe or the return hot water cold pipe, and the return hot water intermediate temperature pipe connected to the mixing valve inlet pipe by piping;

  According to a fourth aspect of the present invention, in the hot water storage hot water supply system according to any one of the first to third aspects, the mixed hot water return pipe supplies the hot water return source to the hot water storage tank as the mixed hot water pipe or a high temperature. A third three-way valve for switching to any one of the hot water return pipes branched from the hot water supply pipe is provided.

  According to the first aspect of the present invention, the hot water in the mixed hot water pipe whose temperature has been lowered by the hot water supply pump is returned to the hot water storage tank, and the hot water in the hot water storage tank, the mixed hot water in the hot water supply water, and the mixed hot water are supplied to the mixed hot water pipe. Since the hot water is supplied and the hot water temperature in the mixed hot water pipe is maintained, as soon as the outlet of the mixed hot water pipe is opened, the medium temperature mixed hot water is discharged. Moreover, since the hot water in the mixed hot water pipe and the hot water storage tank is not circulated and discarded, the hot water is not wasted.

  According to the invention of claim 2, since the hot water in the mixed hot water pipe is returned to the hot water storage tank through the mixing valve water pipe, the same effect as in the first aspect can be obtained. Moreover, since the mixed hot water pipe is connected to the mixing valve water pipe without being connected to the hot water storage tank, the length of the mixed hot water pipe may be short and the cost can be reduced.

  According to the invention of claim 3, since the hot water in the mixed hot water pipe is returned to the hot water storage tank via the second three-way valve, the same effect as in claim 1 can be obtained. In addition, since the hot water return destination can be switched to either the middle layer of the hot water storage tank or the water supply pipe according to the temperature of the mixed hot water in the hot water mixing pipe, the temperature stratification is achieved without disturbing the hot water temperature distribution in the hot water storage tank. Is easily maintained, and hot and medium hot water can be discharged efficiently.

  According to the invention of claim 4, since the hot water in the hot water supply pipe and the hot water in the mixed hot water pipe are returned by the same pipe, the cost is reduced.

The block diagram of the hot water storage type hot-water supply system which concerns on the 1st Embodiment of this invention. The block diagram of the hot water storage type hot-water supply system which concerns on the 1st modification of embodiment same as the above. The block diagram of the hot water storage type hot-water supply system which concerns on the 2nd modification of embodiment same as the above. The block diagram of the hot water storage type hot-water supply system which concerns on the 2nd Embodiment of this invention. The block diagram of the conventional hot water storage type hot-water supply system.

(First embodiment)
A hot water storage type hot water supply system (hereinafter referred to as a hot water supply system) according to a first embodiment of the present invention will be described with reference to FIG. A hot water supply system 1 includes a hot water storage tank 2 that stores hot water and heated hot water, a heat pump (heating source) 3 that heats water in the hot water storage tank 2, a control unit 4 that controls the operation of the heat pump 3, and the like, and a hot water storage tank 2 is provided with a hot water supply pipe 5 for supplying hot water in the hot water 2 and a mixed hot water pipe 6 for supplying hot water mixed with hot water in the hot water storage tank 2. Here, the hot water is approximately 75 ° C. or higher, and the mixed hot water is approximately 35 to 45 ° C.

  The hot water storage tank 2 has a plurality of temperature sensors 21 on the side wall from the upper part to the lower part, and the control unit 4 detects the amount of hot water in the hot water storage tank 2 from the hot water temperature detected by the temperature sensor 21. The lower layer portion of the hot water storage tank 2 is connected to a water supply pipe 71 that supplies water. Further, the lower layer portion of the hot water storage tank 2 is connected to the heat pump 3 via the pipe 72, and the lower layer water of the hot water storage tank 2 is heated by the heat pump 3. The heat pump 3 has a pump 31 that sends heated hot water to the hot water storage tank 2. The heat pump 3 is connected to the upper layer portion of the hot water storage tank 2 via a pipe 73 and supplies heated hot water to the upper layer portion of the hot water storage tank 2.

  The upper layer portion of the hot water storage tank 2 is connected to a high temperature hot water supply port 51 via a high temperature hot water supply pipe 5, and the high temperature hot water supply pipe 5 is provided with a temperature sensor 52 for detecting the temperature of the hot water in the pipe. A high temperature return pipe 53 for returning hot water in the high temperature hot water supply pipe 5 to the hot water storage tank 2 is branched from the vicinity of the high temperature hot water supply pipe 51 of the high temperature hot water supply pipe 5. A hot water pump 54 is provided.

  The mixed hot water supply pipe 6 includes a high temperature hot water supply pipe 61 branched from the high temperature hot water supply pipe 5, a medium temperature hot water supply pipe 62 for taking out hot water in the middle layer of the hot water storage tank 2, and a three-way valve that connects the high temperature hot water supply pipe 61 and the intermediate temperature hot water supply pipe 62. 63, a mixing valve hot water pipe 64 connected to the three-way valve 63, a mixing valve water inlet pipe 65 branched from the water supply pipe 71, a mixed hot water from the mixing valve hot water pipe 64, and a water supply from the mixing valve water inlet pipe 65 And a mixing hot water pipe 68 that connects the mixing valve 66 and the mixing hot water supply port 67. The high temperature hot water supply pipe 61 may be connected to the upper layer portion of the hot water storage tank 2 without branching from the high temperature hot water supply pipe 5. The mixed hot water pipe 68 is provided with a temperature sensor 69 for detecting the hot water temperature in the pipe. A mixed hot water pipe 81 for returning hot water in the mixed hot water pipe 68 to the hot water storage tank 2 is branched from the vicinity of the mixed hot water inlet 67 of the mixed hot water pipe 68. A hot water pump 82 is provided. The hot-water supply pump 54 and the hot-water supply pump 82 are configured such that hot water in the pipe does not flow backward when stopped.

  Next, the operation of the hot water supply system 1 will be described. When the high temperature hot water supply port 51 is opened, the water supplied from the water supply pipe 71 enters the lower layer of the hot water storage tank 2 by the water supply pressure, and the high temperature hot water in the upper layer of the hot water storage tank 2 is pushed up and passes through the high temperature hot water supply pipe 5. Hot water is supplied from the mouth 51. When the mixed hot water supply port 67 is opened, the control unit 4 determines that the three-way valve 63 is set when the set temperature of the mixed hot water set by the user through the control panel (not shown) is higher than the hot water temperature in the middle layer of the hot water storage tank 2. Is switched to the high temperature hot water discharge pipe 61 side, and when the temperature is lower than the hot water temperature in the middle layer of the hot water storage tank 2, the three-way valve 63 is switched to the intermediate temperature hot water discharge pipe 62 side. The hot water from the switched hot water outlet pipe and the feed water from the mixing valve inlet pipe 65 are sent to the mixing valve 66 by the feed water pressure, and mixed hot water is supplied from the mixed hot water outlet 67 through the mixed hot water pipe 68. At this time, the control unit 4 mixes the mixing ratio of the hot water from the mixing valve hot water pipe 64 and the feed water from the mixing valve water pipe 65 so that the hot water temperature of the mixed hot water detected by the temperature sensor 69 becomes the set temperature. 66. When the hot water temperature of the mixed hot water is low, the mixing ratio of the hot water from the mixing valve hot water pipe 64 is increased, and when the hot water temperature of the mixed hot water is high, the mixing ratio of the feed water from the mixing valve water inlet pipe 65 is increased. To do.

  When the control unit 4 determines that the amount of hot water in the hot water storage tank 2 is less than a predetermined amount based on the hot water temperature detected by the temperature sensor 21, the control unit 4 drives the pump 31 to supply water in the lower layer of the hot water storage tank 2. And is heated by the heat pump 3 and supplied to the upper layer portion of the hot water storage tank 2 through the pipe 73. The control unit 4 continues to drive the pump 31 and heat the supplied water until the amount of hot water in the hot water storage tank 2 increases to a predetermined amount.

  When the hot water temperature in the high temperature hot water supply pipe 5 detected by the temperature sensor 52 becomes lower than a predetermined temperature, the hot water supply pump 54 is driven. Hot water in the high temperature hot water supply pipe 5 is returned to the middle layer of the hot water storage tank 2 through the high temperature hot water return pipe 53, and high temperature hot water in the upper layer of the hot water storage tank 2 is sent to the high temperature hot water supply pipe 5. Hot water in the return pipe 53 is circulated. When the hot water temperature detected by the temperature sensor 52 becomes higher than a predetermined temperature, the drive of the hot water supply pump 54 is stopped. In this way, the hot water temperature in the high temperature hot water supply pipe 5 is always equal to or higher than the predetermined temperature, so that when the high temperature hot water supply port 51 is opened, the high temperature hot water is discharged immediately.

  Further, when the hot water temperature in the mixed hot water pipe 68 detected by the temperature sensor 69 becomes lower than a predetermined temperature, the hot water supply pump 82 is driven and the hot water in the mixed hot water pipe 68 passes through the mixed hot water pipe 81. Returned to the middle layer of 2. By the hot water returned to the middle layer, the high temperature hot water in the upper layer of the hot water storage tank 2 comes from the high temperature hot water discharge pipe 61 and the middle temperature hot water from the middle temperature hot water discharge pipe 62 passes along the path indicated by the arrow A in the figure. Then, hot water is fed to the mixing valve 66 through the mixing valve hot water pipe 64. Further, the water in the lower layer is fed from the water supply pipe 71 to the mixing valve 66 through the mixing valve inlet pipe 65 along the path indicated by the arrow B in the figure. At this time, the control unit 4 switches the three-way valve 63 to one of the hot water discharge pipe 61 and the medium temperature hot water discharge pipe 62 according to the set temperature of the mixed hot water. In addition, the control unit 4 sets the mixing ratio of the mixing ratio of the hot water from the mixing valve inlet pipe 64 and the supply water from the mixing valve inlet pipe 65 so that the hot water temperature of the mixed hot water detected by the temperature sensor 69 becomes the set temperature. 66.

  When the hot water temperature detected by the temperature sensor 69 reaches the set temperature of the mixed hot water, the drive of the hot water supply pump 82 is stopped. In this way, the hot water temperature in the mixed hot water pipe 68 always becomes the set temperature, so that the mixed hot water at the set temperature is immediately discharged when the mixed hot water supply port 67 is opened, so that convenience is improved. Moreover, hot water is not wasted. Moreover, since hot water is used according to the lack of hot water temperature, there is no waste of energy.

(First modification)
Next, a first modification of the present embodiment will be described with reference to FIG. In this modification, the hot water return destination of the mixed hot water in the mixed hot water pipe 68 is different from that of the embodiment. The mixed hot water return pipe 81 is not connected to the hot water storage tank 2 but connected to the mixing valve water intake pipe 65. When the hot water supply pump 82 is driven, a part of the hot water in the mixed hot water pipe 68 is mixed with the mixing valve 66 via the mixed hot water pipe 81 and the mixing valve water inlet pipe 65 along the path indicated by the arrow C in the drawing. Hot water is sent to. The remaining hot water in the mixed hot water pipe 68 is sent to the lower layer of the hot water storage tank 2 through the mixed hot water pipe 81, the mixing valve water pipe 65, and the water supply pipe 71 along the path indicated by the arrow D in the figure. Hot water is supplied to the mixing valve 66 through the three-way valve 63 and the mixing valve hot water inlet pipe 64 through the high temperature hot water outlet pipe 61 or the intermediate temperature hot water outlet pipe 62. The control unit 4 uses the mixing valve 66 to change the mixing ratio of the hot water from the mixing valve inlet pipe 64 and the feed water from the mixing valve inlet pipe 65 so that the hot water temperature of the mixed hot water detected by the temperature sensor 69 becomes the set temperature. adjust.

  In this manner, the hot water temperature in the mixed hot water pipe 68 is always set to the set temperature as in the first embodiment, so that the same effect as in the first embodiment can be obtained. Further, by using a part of the returned hot water generated in the circulation as water to be put into the mixing valve 66, the returned hot water has a temperature higher than that of the water. Therefore, the amount of hot water required to bring the mixed hot water to the set temperature is reduced. Therefore, it is possible to reduce the amount of hot water stored in the hot water storage tank 2. In addition, since the mixed hot water pipe 81 is connected to the mixed valve water pipe 65 without being connected to the hot water storage tank 2, the length of the mixed hot water pipe 81 is shortened and the cost is reduced.

(Second modification)
Next, a second modification of the present embodiment will be described with reference to FIG. In this modification, the hot water return destination of the mixed hot water in the mixed hot water pipe 68 is different from that of the embodiment. The mixed hot water return pipe 81 has a second three-way valve 83 for switching the hot water return destination of the mixed hot water. The hot water supply intermediate temperature pipe 84 and the water supply pipe 71 connected to the middle layer of the hot water storage tank 2 through the second three-way valve 83 are provided. It branches off to a connected hot water cryogenic pipe 85. The returning hot water intermediate pipe 84 is connected to the mixing valve inlet pipe 65 by a pipe 86. The return hot water intermediate pipe 84 and the return hot water cold pipe 85 are provided with check valves 87 and 87 for preventing a back flow from the hot water storage tank 2 and the water supply pipe 71. An opening / closing valve 88 is provided in the mixing valve inlet pipe 65. The second three-way valve 83 switches the hot water destination to the hot water intermediate temperature pipe 84 or the hot water cold pipe 85 based on the hot water temperature of the mixed hot water to be returned.

  Next, the operation of the hot water supply system 1 will be described. When the hot water temperature in the mixed hot water pipe 68 detected by the temperature sensor 69 becomes lower than a predetermined temperature, the hot water supply pump 82 is driven. At this time, when the hot water temperature in the mixed hot water pipe 68 is higher than a predetermined reference temperature for switching the second three-way valve 83, the second three-way valve 83 is switched to the hot water intermediate temperature pipe 84. At this time, the on-off valve 88 is closed in order to prevent hot water supply from the water supply pipe 71 to the mixing valve inlet pipe 65. A part of the mixed hot water in the mixed hot water pipe 68 passes through the mixed return hot water pipe 81 and the second three-way valve 83, and thereafter, the mixed valve passes through the pipe 86 and the mixed valve water inlet pipe 65 along the arrow E in the figure. The hot water is sent to 66. The remainder of the mixed hot water in the mixed hot water pipe 68 passes through the mixed hot water return pipe 81 and the second three-way valve 83, and thereafter, the middle layer of the hot water storage tank 2 through the hot water intermediate hot pipe 84 along the arrow F in the figure. The hot water is fed to the hot water outlet pipe 61 or the intermediate hot water hot water pipe 62 and fed to the mixing valve 66 via the three-way valve 63 and the mixing valve hot water pipe 64. At this time, the path for supplying hot water from the hot water storage tank 2 to the mixing valve 66 through the water supply pipe 71 and the mixing valve inlet pipe 65 is closed by the on-off valve 88.

  When the hot water temperature in the mixed hot water pipe 68 is lower than a predetermined reference temperature for switching the second three-way valve 83, the second three-way valve 83 is switched to the hot water cold pipe 85. At this time, the on-off valve 88 is opened. Part of the mixed hot water in the mixed hot water pipe 68 passes through the mixed hot water return pipe 81 and the second three-way valve 83, and thereafter, along the arrow G in the figure, the hot water return cold pipe 85, the water supply pipe 71, and the mixing valve enter. Hot water is fed to the mixing valve 66 through the water pipe 65. The remainder of the mixed hot water in the mixed hot water pipe 68 is sent to the lower layer of the hot water storage tank 2 through the mixed hot water pipe 81, the second three-way valve 83, the hot water cold pipe 85, and the water supply pipe 71, and the hot hot water pipe. The hot water is fed to the mixing valve 66 through the three-way valve 63 and the mixing valve hot water pipe 64 through 61 or the medium temperature hot water pipe 62. The control unit 4 uses the mixing valve 66 to change the mixing ratio of the hot water from the mixing valve inlet pipe 64 and the feed water from the mixing valve inlet pipe 65 so that the hot water temperature of the mixed hot water detected by the temperature sensor 69 becomes the set temperature. adjust.

  In this manner, the hot water temperature in the mixed hot water pipe 68 is always set to the set temperature as in the first embodiment, so that the same effect as in the first embodiment can be obtained. Further, since the hot water return destination is switched to either the middle layer of the hot water storage tank 2 or the water supply pipe 71 in accordance with the temperature of the mixed hot water in the mixed hot water pipe 68, the temperature stratification is not disturbed. Is easily maintained, and hot and medium hot water can be discharged efficiently.

(Second Embodiment)
A hot water supply system according to a second embodiment of the present invention will be described with reference to FIG. In the present embodiment, the hot water in the hot water supply pipe 5 and the mixed hot water in the mixed hot water pipe 68 are returned by the same pipe. The mixed hot water return pipe 81 has a third three-way valve 89 that switches the hot water return source to the hot water storage tank 2 to either the mixed hot water pipe 68 or the high temperature hot water supply pipe 53 branched from the high temperature hot water supply pipe 5. When the hot water temperature in the high temperature hot water supply pipe 5 detected by the temperature sensor 52 becomes lower than a predetermined temperature, the third three-way valve 89 is switched to the high temperature hot water return pipe 53 and the hot water supply pump 82 is driven. Hot water in the high temperature hot water supply pipe 5 is returned to the middle layer portion of the hot water storage tank 2 through the high temperature hot water return pipe 53, the third three-way valve 89, and the mixed hot water return pipe 81. When the hot water temperature in the mixed hot water pipe 68 detected by the temperature sensor 69 becomes lower than a predetermined temperature, the third three-way valve 89 is switched to the mixed hot water pipe 81, the hot water supply pump 82 is driven, and the mixed hot water pipe is driven. The hot water in 68 is returned to the middle layer of the hot water storage tank 2 through the mixed hot water return pipe 81 and the third three-way valve 89. Thus, since the hot water in the hot water supply pipe 5 and the hot water in the mixed hot water pipe 68 are returned by the same pipe, the cost is reduced. Such a configuration in which the hot water in the hot water supply pipe 5 and the mixed hot water in the mixed hot water pipe 68 are returned by the same pipe may be applied to each modification of the first embodiment described above.

  In addition, this invention is not restricted to the structure of the said embodiment, A various deformation | transformation is possible in the range which does not change the meaning of invention. For example, instead of being based on the hot water temperature in the mixed hot water pipe 68, the hot water supply pump 82 may be driven according to time to circulate the hot water in the mixed hot water pipe 68 and the hot water in the hot water storage tank 2. In the first embodiment, the high temperature hot water return pipe 53 and the hot water supply pump 54 are not provided, and the hot water may not be returned.

1 Hot water storage hot water supply system 2 Hot water storage tank 3 Heat pump (heating source)
4 Control unit 5 High temperature hot water supply pipe 6 Mixed hot water supply pipe 61 High temperature hot water discharge pipe 62 Medium temperature hot water supply pipe 63 Three-way valve 64 Mixing valve hot water pipe 65 Mixed valve hot water pipe 66 Mixing valve 68 Mixed hot water pipe 71 Hot water pipe 81 Mixed hot water pipe 82 Hot water supply Pump 83 Second three-way valve 84 Return hot water intermediate pipe 85 Return hot water cold pipe 86 Pipe 89 Third three way valve

Claims (4)

A hot water storage tank connected to the water supply pipe for storing the hot water and heated water, a heating source for heating the water in the hot water storage tank, a controller for controlling the operation of the heating source, and hot water for the hot water storage tank A hot water supply pipe that supplies hot water mixed with hot water or hot water in the hot water storage tank mixed with hot water supplied from the water supply pipe, and hot water in the mixed hot water pipe for immediate hot water. In a hot water storage type hot water supply system equipped with a mixed hot water return pipe returning to a hot water storage tank,
The mixed hot water pipe includes a high temperature hot water pipe connected to an upper layer part of the hot water storage tank or the high temperature hot water pipe, an intermediate hot water pipe connected to a middle part of the hot water tank, the high temperature hot water pipe and an intermediate hot water pipe, A three-way valve connecting the three-way valve, a mixing valve inlet pipe connected to the three-way valve for feeding hot water, a mixing valve inlet pipe branched from the water supply pipe, hot water from the mixing valve inlet pipe and water supply from the mixing valve inlet pipe And a mixing hot water pipe for discharging mixed hot water by the mixing valve,
The mixed hot water pipe is branched from the mixed hot water pipe and connected to an intermediate layer which is an intermediate temperature part of the hot water storage tank, and a hot water supply pump for feeding hot water in the mixed hot water pipe to the hot water storage tank is provided. A hot water storage hot water supply system characterized by having. A hot water storage tank connected to the water supply pipe for storing the hot water and heated water, a heating source for heating the water in the hot water storage tank, a controller for controlling the operation of the heating source, and hot water for the hot water storage tank A hot water supply pipe that supplies hot water mixed with hot water or hot water in the hot water storage tank mixed with hot water supplied from the water supply pipe, and hot water in the mixed hot water pipe for immediate hot water. In a hot water storage type hot water supply system equipped with a mixed hot water return pipe returning to a hot water storage tank,
The mixed hot water pipe includes a high temperature hot water pipe connected to an upper layer part of the hot water storage tank or the high temperature hot water pipe, an intermediate hot water pipe connected to a middle part of the hot water tank, the high temperature hot water pipe and an intermediate hot water pipe, A three-way valve connecting the three-way valve, a mixing valve inlet pipe connected to the three-way valve for feeding hot water, a mixing valve inlet pipe branched from the water supply pipe, hot water from the mixing valve inlet pipe and water supply from the mixing valve inlet pipe And a mixing hot water pipe for discharging mixed hot water by the mixing valve,
The mixed hot water pipe is branched from the mixed hot water pipe and connected to the mixing valve water inlet pipe without being connected to the hot water storage tank, and the hot water in the mixed hot water pipe is fed to the mixed valve water inlet pipe. A hot water storage hot water supply system characterized by having a hot water pump. A hot water storage tank connected to the water supply pipe for storing the hot water and heated water, a heating source for heating the water in the hot water storage tank, a controller for controlling the operation of the heating source, and hot water for the hot water storage tank A hot water supply pipe that supplies hot water mixed with hot water or hot water in the hot water storage tank mixed with hot water supplied from the water supply pipe, and hot water in the mixed hot water pipe for immediate hot water. In a hot water storage type hot water supply system equipped with a mixed hot water return pipe returning to a hot water storage tank,
The mixed hot water pipe includes a high temperature hot water pipe connected to an upper layer part of the hot water storage tank or the high temperature hot water pipe, an intermediate hot water pipe connected to a middle part of the hot water tank, the high temperature hot water pipe and an intermediate hot water pipe, A three-way valve connecting the three-way valve, a mixing valve inlet pipe connected to the three-way valve for feeding hot water, a mixing valve inlet pipe branched from the water supply pipe, hot water from the mixing valve inlet pipe and water supply from the mixing valve inlet pipe And a mixing hot water pipe for discharging mixed hot water by the mixing valve,
The mixed hot water pipe branches from the mixed hot water pipe, and a hot water intermediate temperature pipe connected to the hot water storage tank via a second three-way valve that switches a hot water return destination of the mixed hot water, and a hot water cold pipe connected to the water supply pipe, A hot water supply pump for branching the hot water in the mixed hot water pipe to the hot water intermediate temperature pipe or the hot water cold pipe,
The hot water storage hot water supply system characterized in that the hot water return intermediate temperature pipe is connected to the mixing valve inlet pipe by piping.   The said mixed hot water pipe has a 3rd three-way valve which switches the hot water return source to the hot water storage tank to either the said mixed hot water pipe or the high temperature hot water pipe branched from the high temperature hot water supply pipe. The hot water storage type hot water supply system according to any one of claims 1 to 3.

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